The invention relates to a method for manufacturing a composite platform (30) for a fan of an aircraft turbine engine, wherein said platform comprises an elongate wall (32) and is configured to extend between two fan blades (3), said wall comprising an outer aerodynamic surface (32a) and an inner surface (32b), on which a fastening tab is located (34), said fastening tab being configured to be fixed to a fan disc (2). The invention is characterized in that it comprises the steps of: a) preparing fabrics or sheets which are pre-impregnated with a resin, b) depositing the fabrics or sheets in a mold, c) positioning a metal reinforcement (36) in the mold on the fabrics or sheets, the reinforcement being integrally formed with said fastening tab, d) depositing the fabrics or sheets on a part of the reinforcement, and e) closing and heating the mold for solidification of the assembly formed by the fabrics or sheets and the reinforcement.